Text based searching of content has been aided much by electronic computers. Search results are commonly generated by computer-implemented search engines. Search engines are helpful in finding content stored on computers and networks. Search engines are particularly useful in sorting through the vastness of the Internet and the World Wide Web, but they are also used on intranets, smaller networks, and individual machines. Generally, search engines sort results using various methods and based on a number of criteria. Such criteria may include the creation date of particular content, its relevance, or the number of times it has been viewed.
Search engines fall into different categories, such as general purpose consumer oriented search engines and vertical search engines. Historically, general purpose search engines took a one size fits all approach to searching, though more modem solutions have attempted to personalize the search experience and tailor the search results. Vertical search engines are typically used with specific databases and can offer a greater degree of customization in order to find more relevant results. Vertical search engines are often limited in breadth compared to general purpose search engines.